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        <EOYAmt>1369542</EOYAmt>
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      <TotalLiabilitiesGrp>
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        <EOYAmt>0</EOYAmt>
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      <OrgDoesNotFollowFASB117Ind>X</OrgDoesNotFollowFASB117Ind>
      <CapStkTrPrinCurrentFundsGrp>
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        <EOYAmt>0</EOYAmt>
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      <PdInCapSrplsLandBldgEqpFundGrp>
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        <EOYAmt>1369542</EOYAmt>
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      <TotLiabNetAssetsFundBalanceGrp>
        <BOYAmt>1621012</BOYAmt>
        <EOYAmt>1369542</EOYAmt>
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      <ReconcilationRevenueExpnssAmt>-251489</ReconcilationRevenueExpnssAmt>
      <NetUnrlzdGainsLossesInvstAmt>19</NetUnrlzdGainsLossesInvstAmt>
      <DonatedServicesAndUseFcltsAmt>0</DonatedServicesAndUseFcltsAmt>
      <InvestmentExpenseAmt>0</InvestmentExpenseAmt>
      <PriorPeriodAdjustmentsAmt>0</PriorPeriodAdjustmentsAmt>
      <OtherChangesInNetAssetsAmt>0</OtherChangesInNetAssetsAmt>
      <MethodOfAccountingCashInd>X</MethodOfAccountingCashInd>
      <AccountantCompileOrReviewInd>1</AccountantCompileOrReviewInd>
      <AcctCompileOrReviewBasisGrp>
        <SeparateBasisFinclStmtInd>X</SeparateBasisFinclStmtInd>
      </AcctCompileOrReviewBasisGrp>
      <FSAuditedInd>0</FSAuditedInd>
      <AuditCommitteeInd>1</AuditCommitteeInd>
      <FederalGrantAuditRequiredInd>0</FederalGrantAuditRequiredInd>
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    <IRS990ScheduleA documentId="R000002" softwareId="24021167" softwareVersionNum="v1.00">
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        <CurrentTaxYearMinus3YearsAmt>484882</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>532084</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>523420</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>540595</CurrentTaxYearAmt>
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        <CurrentTaxYearMinus3YearsAmt>484882</CurrentTaxYearMinus3YearsAmt>
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        <CurrentTaxYearMinus1YearAmt>523420</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>540595</CurrentTaxYearAmt>
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      <PublicSupportTotal509Amt>2600300</PublicSupportTotal509Amt>
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        <CurrentTaxYearMinus3YearsAmt>8908</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>1530</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>4749</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>3568</CurrentTaxYearAmt>
        <TotalAmt>52451</TotalAmt>
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      <InvestmentIncomeAndUBTIGrp>
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        <CurrentTaxYearMinus3YearsAmt>8908</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>1530</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>4749</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>3568</CurrentTaxYearAmt>
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        <CurrentTaxYearMinus3YearsAmt>527774</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>533614</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>705163</CurrentTaxYearMinus1YearAmt>
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      <InvestmentIncomePYPct>0.0147</InvestmentIncomePYPct>
      <ThirtyThrPctSuprtTestsPY509Ind>X</ThirtyThrPctSuprtTestsPY509Ind>
      <Form990ScheduleAPartVIGrp>
        <FormAndLineReferenceDesc>Schedule A, Part III, Line 12</FormAndLineReferenceDesc>
        <ExplanationTxt>These are the sporadic income from the quadrennial International Geological Congresses, for which the IUGS receives a capitation fee.</ExplanationTxt>
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    <IRS990ScheduleO documentId="R000003" softwareId="24021167" softwareVersionNum="v1.00">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Section A, Line 6</FormAndLineReferenceDesc>
        <ExplanationTxt>The active members are the national bodies (typically scientific academies or national geological societies) who have paid their subscription for the year. The IUGS currently has 57 active members (referred as "active adhering members") and 66 that are inactive. There are 57 affiliated geoscientific organisations.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Section A, Line 7a</FormAndLineReferenceDesc>
        <ExplanationTxt>The 57 national bodies that are the members can elect people from those organisation to the Governing Body (in this case the IUGS Executive Committee). Such elected individuals are acting individually (not as representatives of the national bodies) and must act in the interests of the IUGS while on that Executive Committee.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Section A, Line 7b</FormAndLineReferenceDesc>
        <ExplanationTxt>The members elect the executive committee and determine the location of the quadrennial International Geological Congress.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Section B, Line 11b</FormAndLineReferenceDesc>
        <ExplanationTxt>The financial details are based on the report of the Treasurer to the Executive Committee that is presented prior to completing the 990 return.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Section C, Line 19</FormAndLineReferenceDesc>
        <ExplanationTxt>These can be made available on request, and are available to the national member organisations. IUGS's governing documents are published in IUGS's website, its financial statements are published yearly in "EPISODES" - the IUGS journal</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
  </ReturnData>
</Return>